diff --git a/assets/lunr.multi.js b/assets/lunr.multi.js
deleted file mode 100644
index 4e921e02..00000000
--- a/assets/lunr.multi.js
+++ /dev/null
@@ -1,79 +0,0 @@
-/**
- * export the module via AMD, CommonJS or as a browser global
- * Export code from https://github.com/umdjs/umd/blob/master/returnExports.js
- */
-;(function (root, factory) {
-    if (typeof define === 'function' && define.amd) {
-        // AMD. Register as an anonymous module.
-        define(factory)
-    } else if (typeof exports === 'object') {
-        /**
-         * Node. Does not work with strict CommonJS, but
-         * only CommonJS-like environments that support module.exports,
-         * like Node.
-         */
-        module.exports = factory()
-    } else {
-        // Browser globals (root is window)
-        factory()(root.lunr);
-    }
-}(this, function () {
-    /**
-     * Just return a value to define the module export.
-     * This example returns an object, but the module
-     * can return a function as the exported value.
-     */
-    return function(lunr) {
-        /* Set up the pipeline for indexing content in multiple languages. The
-           corresponding lunr.{lang} files must be loaded before calling this
-           function; English ('en') is built in.
-
-           Returns: a lunr plugin for use in your indexer.
-
-           Known drawback: every word will be stemmed with stemmers for every
-           language. This could mean that sometimes words that have the same
-           stemming root will not be stemmed as such.
-           */
-        lunr.multiLanguage = function(/* lang1, lang2, ... */) {
-            var languages = Array.prototype.slice.call(arguments);
-            var nameSuffix = languages.join('-');
-            var wordCharacters = "";
-            var pipeline = [];
-            var searchPipeline = [];
-            for (var i = 0; i < languages.length; ++i) {
-                if (languages[i] == 'en') {
-                    wordCharacters += '\\w';
-                    pipeline.unshift(lunr.stopWordFilter);
-                    pipeline.push(lunr.stemmer);
-                    searchPipeline.push(lunr.stemmer);
-                } else {
-                    wordCharacters += lunr[languages[i]].wordCharacters;
-                    if (lunr[languages[i]].stopWordFilter) {
-                        pipeline.unshift(lunr[languages[i]].stopWordFilter);
-                    }
-                    if (lunr[languages[i]].stemmer) {
-                        pipeline.push(lunr[languages[i]].stemmer);
-                        searchPipeline.push(lunr[languages[i]].stemmer);
-                    }
-                }
-            };
-            var multiTrimmer = lunr.trimmerSupport.generateTrimmer(wordCharacters);
-            lunr.Pipeline.registerFunction(multiTrimmer, 'lunr-multi-trimmer-' + nameSuffix);
-            pipeline.unshift(multiTrimmer);
-
-            return function() {
-                this.pipeline.reset();
-
-                this.pipeline.add.apply(this.pipeline, pipeline);
-
-                // for lunr version 2
-                // this is necessary so that every searched word is also stemmed before
-                // in lunr <= 1 this is not needed, as it is done using the normal pipeline
-                if (this.searchPipeline) {
-                    this.searchPipeline.reset();
-                    this.searchPipeline.add.apply(this.searchPipeline, searchPipeline);
-                }
-            };
-        }
-    }
-}));
diff --git a/assets/lunr.stemmer.support.js b/assets/lunr.stemmer.support.js
deleted file mode 100644
index 896476a1..00000000
--- a/assets/lunr.stemmer.support.js
+++ /dev/null
@@ -1,304 +0,0 @@
-/*!
- * Snowball JavaScript Library v0.3
- * http://code.google.com/p/urim/
- * http://snowball.tartarus.org/
- *
- * Copyright 2010, Oleg Mazko
- * http://www.mozilla.org/MPL/
- */
-
-/**
- * export the module via AMD, CommonJS or as a browser global
- * Export code from https://github.com/umdjs/umd/blob/master/returnExports.js
- */
-;(function (root, factory) {
-    if (typeof define === 'function' && define.amd) {
-        // AMD. Register as an anonymous module.
-        define(factory)
-    } else if (typeof exports === 'object') {
-        /**
-         * Node. Does not work with strict CommonJS, but
-         * only CommonJS-like environments that support module.exports,
-         * like Node.
-         */
-        module.exports = factory()
-    } else {
-        // Browser globals (root is window)
-        factory()(root.lunr);
-    }
-}(this, function () {
-    /**
-     * Just return a value to define the module export.
-     * This example returns an object, but the module
-     * can return a function as the exported value.
-     */
-    return function(lunr) {
-        /* provides utilities for the included stemmers */
-        lunr.stemmerSupport = {
-            Among: function(s, substring_i, result, method) {
-                this.toCharArray = function(s) {
-                    var sLength = s.length, charArr = new Array(sLength);
-                    for (var i = 0; i < sLength; i++)
-                        charArr[i] = s.charCodeAt(i);
-                    return charArr;
-                };
-
-                if ((!s && s != "") || (!substring_i && (substring_i != 0)) || !result)
-                    throw ("Bad Among initialisation: s:" + s + ", substring_i: "
-                        + substring_i + ", result: " + result);
-                this.s_size = s.length;
-                this.s = this.toCharArray(s);
-                this.substring_i = substring_i;
-                this.result = result;
-                this.method = method;
-            },
-            SnowballProgram: function() {
-                var current;
-                return {
-                    bra : 0,
-                    ket : 0,
-                    limit : 0,
-                    cursor : 0,
-                    limit_backward : 0,
-                    setCurrent : function(word) {
-                        current = word;
-                        this.cursor = 0;
-                        this.limit = word.length;
-                        this.limit_backward = 0;
-                        this.bra = this.cursor;
-                        this.ket = this.limit;
-                    },
-                    getCurrent : function() {
-                        var result = current;
-                        current = null;
-                        return result;
-                    },
-                    in_grouping : function(s, min, max) {
-                        if (this.cursor < this.limit) {
-                            var ch = current.charCodeAt(this.cursor);
-                            if (ch <= max && ch >= min) {
-                                ch -= min;
-                                if (s[ch >> 3] & (0X1 << (ch & 0X7))) {
-                                    this.cursor++;
-                                    return true;
-                                }
-                            }
-                        }
-                        return false;
-                    },
-                    in_grouping_b : function(s, min, max) {
-                        if (this.cursor > this.limit_backward) {
-                            var ch = current.charCodeAt(this.cursor - 1);
-                            if (ch <= max && ch >= min) {
-                                ch -= min;
-                                if (s[ch >> 3] & (0X1 << (ch & 0X7))) {
-                                    this.cursor--;
-                                    return true;
-                                }
-                            }
-                        }
-                        return false;
-                    },
-                    out_grouping : function(s, min, max) {
-                        if (this.cursor < this.limit) {
-                            var ch = current.charCodeAt(this.cursor);
-                            if (ch > max || ch < min) {
-                                this.cursor++;
-                                return true;
-                            }
-                            ch -= min;
-                            if (!(s[ch >> 3] & (0X1 << (ch & 0X7)))) {
-                                this.cursor++;
-                                return true;
-                            }
-                        }
-                        return false;
-                    },
-                    out_grouping_b : function(s, min, max) {
-                        if (this.cursor > this.limit_backward) {
-                            var ch = current.charCodeAt(this.cursor - 1);
-                            if (ch > max || ch < min) {
-                                this.cursor--;
-                                return true;
-                            }
-                            ch -= min;
-                            if (!(s[ch >> 3] & (0X1 << (ch & 0X7)))) {
-                                this.cursor--;
-                                return true;
-                            }
-                        }
-                        return false;
-                    },
-                    eq_s : function(s_size, s) {
-                        if (this.limit - this.cursor < s_size)
-                            return false;
-                        for (var i = 0; i < s_size; i++)
-                            if (current.charCodeAt(this.cursor + i) != s.charCodeAt(i))
-                                return false;
-                        this.cursor += s_size;
-                        return true;
-                    },
-                    eq_s_b : function(s_size, s) {
-                        if (this.cursor - this.limit_backward < s_size)
-                            return false;
-                        for (var i = 0; i < s_size; i++)
-                            if (current.charCodeAt(this.cursor - s_size + i) != s
-                                .charCodeAt(i))
-                                return false;
-                        this.cursor -= s_size;
-                        return true;
-                    },
-                    find_among : function(v, v_size) {
-                        var i = 0, j = v_size, c = this.cursor, l = this.limit, common_i = 0, common_j = 0, first_key_inspected = false;
-                        while (true) {
-                            var k = i + ((j - i) >> 1), diff = 0, common = common_i < common_j
-                                ? common_i
-                                : common_j, w = v[k];
-                            for (var i2 = common; i2 < w.s_size; i2++) {
-                                if (c + common == l) {
-                                    diff = -1;
-                                    break;
-                                }
-                                diff = current.charCodeAt(c + common) - w.s[i2];
-                                if (diff)
-                                    break;
-                                common++;
-                            }
-                            if (diff < 0) {
-                                j = k;
-                                common_j = common;
-                            } else {
-                                i = k;
-                                common_i = common;
-                            }
-                            if (j - i <= 1) {
-                                if (i > 0 || j == i || first_key_inspected)
-                                    break;
-                                first_key_inspected = true;
-                            }
-                        }
-                        while (true) {
-                            var w = v[i];
-                            if (common_i >= w.s_size) {
-                                this.cursor = c + w.s_size;
-                                if (!w.method)
-                                    return w.result;
-                                var res = w.method();
-                                this.cursor = c + w.s_size;
-                                if (res)
-                                    return w.result;
-                            }
-                            i = w.substring_i;
-                            if (i < 0)
-                                return 0;
-                        }
-                    },
-                    find_among_b : function(v, v_size) {
-                        var i = 0, j = v_size, c = this.cursor, lb = this.limit_backward, common_i = 0, common_j = 0, first_key_inspected = false;
-                        while (true) {
-                            var k = i + ((j - i) >> 1), diff = 0, common = common_i < common_j
-                                ? common_i
-                                : common_j, w = v[k];
-                            for (var i2 = w.s_size - 1 - common; i2 >= 0; i2--) {
-                                if (c - common == lb) {
-                                    diff = -1;
-                                    break;
-                                }
-                                diff = current.charCodeAt(c - 1 - common) - w.s[i2];
-                                if (diff)
-                                    break;
-                                common++;
-                            }
-                            if (diff < 0) {
-                                j = k;
-                                common_j = common;
-                            } else {
-                                i = k;
-                                common_i = common;
-                            }
-                            if (j - i <= 1) {
-                                if (i > 0 || j == i || first_key_inspected)
-                                    break;
-                                first_key_inspected = true;
-                            }
-                        }
-                        while (true) {
-                            var w = v[i];
-                            if (common_i >= w.s_size) {
-                                this.cursor = c - w.s_size;
-                                if (!w.method)
-                                    return w.result;
-                                var res = w.method();
-                                this.cursor = c - w.s_size;
-                                if (res)
-                                    return w.result;
-                            }
-                            i = w.substring_i;
-                            if (i < 0)
-                                return 0;
-                        }
-                    },
-                    replace_s : function(c_bra, c_ket, s) {
-                        var adjustment = s.length - (c_ket - c_bra), left = current
-                            .substring(0, c_bra), right = current.substring(c_ket);
-                        current = left + s + right;
-                        this.limit += adjustment;
-                        if (this.cursor >= c_ket)
-                            this.cursor += adjustment;
-                        else if (this.cursor > c_bra)
-                            this.cursor = c_bra;
-                        return adjustment;
-                    },
-                    slice_check : function() {
-                        if (this.bra < 0 || this.bra > this.ket || this.ket > this.limit
-                            || this.limit > current.length)
-                            throw ("faulty slice operation");
-                    },
-                    slice_from : function(s) {
-                        this.slice_check();
-                        this.replace_s(this.bra, this.ket, s);
-                    },
-                    slice_del : function() {
-                        this.slice_from("");
-                    },
-                    insert : function(c_bra, c_ket, s) {
-                        var adjustment = this.replace_s(c_bra, c_ket, s);
-                        if (c_bra <= this.bra)
-                            this.bra += adjustment;
-                        if (c_bra <= this.ket)
-                            this.ket += adjustment;
-                    },
-                    slice_to : function() {
-                        this.slice_check();
-                        return current.substring(this.bra, this.ket);
-                    },
-                    eq_v_b : function(s) {
-                        return this.eq_s_b(s.length, s);
-                    }
-                };
-            }
-        };
-
-        lunr.trimmerSupport = {
-            generateTrimmer: function(wordCharacters) {
-                var startRegex = new RegExp("^[^" + wordCharacters + "]+")
-                var endRegex = new RegExp("[^" + wordCharacters + "]+$")
-
-                return function(token) {
-                    // for lunr version 2
-                    if (typeof token.update === "function") {
-                        return token.update(function (s) {
-                            return s
-                                .replace(startRegex, '')
-                                .replace(endRegex, '');
-                        })
-                    } else { // for lunr version 1
-                        return token
-                            .replace(startRegex, '')
-                            .replace(endRegex, '');
-                    }
-                };
-            }
-        }
-    }
-}));
diff --git a/assets/lunr.zh.js b/assets/lunr.zh.js
deleted file mode 100644
index 14a177c0..00000000
--- a/assets/lunr.zh.js
+++ /dev/null
@@ -1,145 +0,0 @@
-/*!
- * Lunr languages, `Chinese` language
- * https://github.com/MihaiValentin/lunr-languages
- *
- * Copyright 2019, Felix Lian (repairearth)
- * http://www.mozilla.org/MPL/
- */
-/*!
- * based on
- * Snowball zhvaScript Library v0.3
- * http://code.google.com/p/urim/
- * http://snowball.tartarus.org/
- *
- * Copyright 2010, Oleg Mazko
- * http://www.mozilla.org/MPL/
- */
-
-/**
- * export the module via AMD, CommonJS or as a browser global
- * Export code from https://github.com/umdjs/umd/blob/master/returnExports.js
- */
-;
-(function(root, factory) {
-  if (typeof define === 'function' && define.amd) {
-    // AMD. Register as an anonymous module.
-    define(factory)
-  } else if (typeof exports === 'object') {
-    /**
-     * Node. Does not work with strict CommonJS, but
-     * only CommonJS-like environments that support module.exports,
-     * like Node.
-     */
-    module.exports = factory(require('nodejieba'))
-  } else {
-    // Browser globals (root is window)
-    factory()(root.lunr);
-  }
-}(this, function(nodejieba) {
-  /**
-   * Just return a value to define the module export.
-   * This example returns an object, but the module
-   * can return a function as the exported value.
-   */
-  return function(lunr, nodejiebaDictJson) {
-    /* throw error if lunr is not yet included */
-    if ('undefined' === typeof lunr) {
-      throw new Error('Lunr is not present. Please include / require Lunr before this script.');
-    }
-
-    /* throw error if lunr stemmer support is not yet included */
-    if ('undefined' === typeof lunr.stemmerSupport) {
-      throw new Error('Lunr stemmer support is not present. Please include / require Lunr stemmer support before this script.');
-    }
-
-    /*
-    Chinese tokenization is trickier, since it does not
-    take into account spaces.
-    Since the tokenization function is represented different
-    internally for each of the Lunr versions, this had to be done
-    in order to try to try to pick the best way of doing this based
-    on the Lunr version
-     */
-    var isLunr2 = lunr.version[0] == "2";
-
-    /* register specific locale function */
-    lunr.zh = function() {
-      this.pipeline.reset();
-      this.pipeline.add(
-        lunr.zh.trimmer,
-        lunr.zh.stopWordFilter,
-        lunr.zh.stemmer
-      );
-
-      // change the tokenizer for Chinese one
-      if (isLunr2) { // for lunr version 2.0.0
-        this.tokenizer = lunr.zh.tokenizer;
-      } else {
-        if (lunr.tokenizer) { // for lunr version 0.6.0
-          lunr.tokenizer = lunr.zh.tokenizer;
-        }
-        if (this.tokenizerFn) { // for lunr version 0.7.0 -> 1.0.0
-          this.tokenizerFn = lunr.zh.tokenizer;
-        }
-      }
-    };
-
-    lunr.zh.tokenizer = function(obj) {
-      if (!arguments.length || obj == null || obj == undefined) return []
-      if (Array.isArray(obj)) return obj.map(function(t) {
-        return isLunr2 ? new lunr.Token(t.toLowerCase()) : t.toLowerCase()
-      })
-
-      nodejiebaDictJson && nodejieba.load(nodejiebaDictJson)
-
-      var str = obj.toString().trim().toLowerCase();
-      var tokens = [];
-
-      nodejieba.cut(str, true).forEach(function(seg) {
-        tokens = tokens.concat(seg.split(' '))
-      })
-
-      tokens = tokens.filter(function(token) {
-        return !!token;
-      });
-
-      var fromIndex = 0
-
-      return tokens.map(function(token, index) {
-        if (isLunr2) {
-          var start = str.indexOf(token, fromIndex)
-
-          var tokenMetadata = {}
-          tokenMetadata["position"] = [start, token.length]
-          tokenMetadata["index"] = index
-
-          fromIndex = start
-
-          return new lunr.Token(token, tokenMetadata);
-        } else {
-          return token
-        }
-      });
-    }
-
-    /* lunr trimmer function */
-    lunr.zh.wordCharacters = "\\w\u4e00-\u9fa5";
-    lunr.zh.trimmer = lunr.trimmerSupport.generateTrimmer(lunr.zh.wordCharacters);
-    lunr.Pipeline.registerFunction(lunr.zh.trimmer, 'trimmer-zh');
-
-    /* lunr stemmer function */
-    lunr.zh.stemmer = (function() {
-
-      /* TODO Chinese stemmer  */
-      return function(word) {
-        return word;
-      }
-    })();
-    lunr.Pipeline.registerFunction(lunr.zh.stemmer, 'stemmer-zh');
-
-    /* lunr stop word filter. see https://www.ranks.nl/stopwords/chinese-stopwords */
-    lunr.zh.stopWordFilter = lunr.generateStopWordFilter(
-      '的 一 不 在 人 有 是 为 以 于 上 他 而 后 之 来 及 了 因 下 可 到 由 这 与 也 此 但 并 个 其 已 无 小 我 们 起 最 再 今 去 好 只 又 或 很 亦 某 把 那 你 乃 它 吧 被 比 别 趁 当 从 到 得 打 凡 儿 尔 该 各 给 跟 和 何 还 即 几 既 看 据 距 靠 啦 了 另 么 每 们 嘛 拿 哪 那 您 凭 且 却 让 仍 啥 如 若 使 谁 虽 随 同 所 她 哇 嗡 往 哪 些 向 沿 哟 用 于 咱 则 怎 曾 至 致 着 诸 自'.split(' '));
-    lunr.Pipeline.registerFunction(lunr.zh.stopWordFilter, 'stopWordFilter-zh');
-  };
-}))
\ No newline at end of file